I've been playing a lot of the new mortal kombat instead. Not even multiplayer, I've been practicing offline. (I played 2 multiplayer matches against 2 scorpions in a row, trashed both of them, both rage quit, so I took a break from multiplayer...)
I've gotten pretty good, and have almost forgotten COD even existed. But I might go back every now and then.
Back when I played COD, depends. 2-3 hours, maybe.
I don't even play every day, I've became more of a casual player when it comes to BO Multiplayer, due to my performance depending more on connection than skill. I do enjoy just playing a match without taking things too seriously though, but yeah couple of matches a week, or less.